Homemade Negative Ion Air Purifier

1. Function and purpose

In addition to filtering the air to purify the air, remove smoke, dust and odor, it can also produce negative oxygen ions. Negative oxygen ions enter the human body through the respiratory tract, which can improve and strengthen the cardiopulmonary function. Negative oxygen ions can exist for 5 to 6 minutes in clean air, but only for about one minute in very polluted air. Therefore, try to use it close to the human breathing area to achieve better results.

2. Working Principle and Installation

The author uses the high-voltage tip discharge method to ionize the air and produce negative oxygen ions. The principle makes the ion generator, that is, the negative ion air freshener. The circuit is shown in Figure 1. The 18W AC voltage output by the secondary of the power transformer T is bridge rectified, stabilized by the three-terminal voltage regulator block 7812, and filtered by the capacitor, and then outputs 11.5v DC voltage to supply the inductive oscillator. The oscillator tube Q uses high-β high-power transistors, such as 3DD200, C5148, D1185, etc., and a heat sink must be added. The high-frequency core high-voltage package components can be found in the electronics market, and the discrete high-voltage package for black and white TVs above 14 inches can also be used. The primary uses the original skeleton L1: Φ0.46mm×45T. L2: Φ0.21mm×90T. L3: Φ0.11mm×2000T. The secondary output coil of the high-voltage package is connected to the high voltage. Diodes D1~D7 and high-voltage capacitors C1~C7 form a seven-fold voltage rectifier circuit, which outputs a DC high voltage of about 20,000 volts, which is discharged into the air through a discharge target. The voltage-doubler rectifier circuit and the high-frequency transformer are poured together with epoxy resin glue. If conditions are not met, rosin can also be melted and poured.

The author installed all the components in the shell of the original 14-inch computer monitor. The discharge needle was pinched off with a 6cm long large needle and 4cm of excess part was pressed on a 24cm long, 2cm wide, 6mm thick organic glass strip according to 8 needles per strip. The needle tip was exposed to the outside with 8mm long, and the needle tail was welded in series with fine copper wire. The exposed wire part was filled with high-voltage insulating glue. The whole screen is divided into five strips up and down, and connected in series with high-voltage insulating wires up and down at the high-voltage output end. The sparking part was sealed with insulating glue. As shown in Figure 3.

3. Circuit adjustment test

Turn on the power, approach the ion generator, there is a strong ion wind, if you use an insulated screwdriver to approach the discharge needle, there is a discharge arc and a "pop" sound. Changing K2 can adjust the strength of the negative ions. If you use the power supply circuit shown in Figure 2, adjusting the sampling potentiometer R10 can fine-tune the output of negative ions from small to large in a wide range. If you use a test pen to approach the discharge needle, a discharge current will be generated in the neon lamp, causing the neon lamp to flicker. Its flickering frequency is proportional to the output of negative ions and inversely proportional to the distance from the emission window. At the same time, you can also qualitatively compare the output of negative oxygen ions from the negative oxygen ion generator you made. If you can't smell the fishy smell 10cm away from the window of the submachine, it means that the ozone concentration does not exceed the standard, that is, the ozone concentration is less than 0.12mg/m3. Please rest assured that dust is easy to accumulate around the purifier for human body, and it should be removed in time. The ion machine should be more than two meters away from the computer host to avoid interference and damage to components. Be careful not to touch the discharge needle when turning on the machine to avoid accidental high voltage output and injury.